Modulation and coding scheme and channel quality indicator for high reliability

ABSTRACT

Certain aspects of the present disclosure provide techniques and apparatus for determining a modulation and coding scheme (MCS) and channel quality indicator (CQI) for ultra-reliable low latency communications (URLLC). An exemplary method generally includes receiving a channel quality indicator (CQI) from a user equipment (UE) and retrieving parameters from a modulation and coding scheme (MCS) table using the CQI, wherein the table has entries corresponding to different spectral efficiency (SE) values selected to allow the BS to efficiently allocate resources at low SE values to achieve at least a target block error rate (BLER). The method also includes sending a transmission to the UE based on the retrieved parameters.

CROSS-REFERENCE TO RELATED APPLICATION & PRIORITY CLAIM

The present Application for patent claims priority to U.S. ProvisionalApplication No. 62/710,479, filed Feb. 16, 2018, which is assigned tothe assignee of the present application and hereby expresslyincorporated by reference herein in its entirety.

BACKGROUND Field of the Disclosure

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to techniques fordetermining a modulation and coding scheme (MCS) and channel qualityindicator (CQI) for ultra-reliable low latency communications (URLLC).

Description of Related Art

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access technologies includeLong Term Evolution (LTE) systems, code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

In some examples, a wireless multiple-access communication system mayinclude a number of base stations, each simultaneously supportingcommunication for multiple communication devices, otherwise known asuser equipment (UEs). In LTE or LTE-A network, a set of one or more basestations may define an e NodeB (eNB). In other examples (e.g., in a nextgeneration or 5G network), a wireless multiple access communicationsystem may include a number of distributed units (DUs) (e.g., edge units(EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs),transmission reception points (TRPs), etc.) in communication with anumber of central units (CUs) (e.g., central nodes (CNs), access nodecontrollers (ANCs), etc.), where a set of one or more distributed units,in communication with a central unit, may define an access node (e.g., anew radio base station (NR BS), a new radio node-B (NR NB), a networknode, 5G NB, gNB, etc.). A base station or DU may communicate with a setof UEs on downlink channels (e.g., for transmissions from a base stationor to a UE) and uplink channels (e.g., for transmissions from a UE to abase station or distributed unit).

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of an emergingtelecommunication standard is new radio (NR), for example, 5G radioaccess. NR is a set of enhancements to the LTE mobile standardpromulgated by Third Generation Partnership Project (3GPP). It isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lowering costs, improving services, making use ofnew spectrum, and better integrating with other open standards usingOFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink(UL) as well as support beamforming, multiple-input multiple-output(MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in NR technology.Preferably, these improvements should be applicable to othermulti-access technologies and the telecommunication standards thatemploy these technologies.

BRIEF SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects of the present disclosure provide a method for wirelesscommunication that may be performed, for example, by a base station(BS). The method generally includes receiving a channel qualityindicator (CQI) from a user equipment (UE) and retrieving parametersfrom a modulation and coding scheme (MCS) table using the CQI, whereinthe table has entries corresponding to different spectral efficiency(SE) values selected to allow the BS to efficiently allocate resourcesat low SE values to achieve at least a target block error rate (BLER).The method also includes sending a transmission to the UE based on theretrieved parameters.

Certain aspects of the present disclosure provide a method for wirelesscommunication that may be performed, for example, by a user equipment(UE). The method generally includes determining a channel qualityindicator (CQI) based on measurement of signals from a base station,determining a rank indicator (RI) value, and signaling the CQI to thebase station, wherein the CQI value is used to indicate the RI value.

Aspects generally include methods, apparatus, systems, computer readablemediums, and processing systems, as substantially described herein withreference to and as illustrated by the accompanying drawings.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 is a block diagram conceptually illustrating an exampletelecommunications system, in accordance with certain aspects of thepresent disclosure.

FIG. 2 is a block diagram illustrating an example logical architectureof a distributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 3 is a diagram illustrating an example physical architecture of adistributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 4 is a block diagram conceptually illustrating a design of anexample BS and user equipment (UE), in accordance with certain aspectsof the present disclosure.

FIG. 5 is a diagram showing examples for implementing a communicationprotocol stack, in accordance with certain aspects of the presentdisclosure.

FIG. 6 illustrates an example of a DL-centric subframe, in accordancewith certain aspects of the present disclosure.

FIG. 7 illustrates an example of an UL-centric subframe, in accordancewith certain aspects of the present disclosure.

FIG. 8 is a flow diagram illustrating example operations that may beperformed by a BS, in accordance with certain aspects of the presentdisclosure.

FIG. 9 is a flow diagram illustrating example operations that may beperformed by a UE, in accordance with certain aspects of the presentdisclosure.

FIG. 10 is an example graph of resource allocation with respect tospectral efficiency, in accordance with certain aspects of the presentdisclosure.

FIG. 11 is an example graph of a performance-related parameter withrespect to spectral efficiency, in accordance with certain aspects ofthe present disclosure.

FIG. 12 illustrates a block diagram of an example wireless communicationdevice, in accordance with certain aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in one aspectmay be beneficially utilized on other aspects without specificrecitation.

DETAILED DESCRIPTION

Aspects of the present disclosure provide apparatus, methods, processingsystems, and computer readable mediums for new radio (NR) (new radioaccess technology or 5G technology). NR may support various wirelesscommunication services, such as Enhanced mobile broadband (eMBB)targeting wide bandwidth (e.g. 80 MHz beyond), millimeter wave (mmW)targeting high carrier frequency (e.g. 60 GHz), massive MTC (mMTC)targeting non-backward compatible MTC techniques, and/or missioncritical targeting ultra-reliable low latency communications (URLLC).These services may include latency and reliability requirements. Theseservices may also have different transmission time intervals (TTI) tomeet respective quality of service (QoS) requirements. In addition,these services may co-exist in the same subframe.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in some other examples. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim. The word “exemplary”is used herein to mean “serving as an example, instance, orillustration.” Any aspect described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects.

The techniques described herein may be used for various wirelesscommunication networks such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA network may implement aradio technology such as Global System for Mobile Communications (GSM).An OFDMA network may implement a radio technology such as NR (e.g. 5GRA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA andE-UTRA are part of Universal Mobile Telecommunication System (UMTS). NRis an emerging wireless communications technology under development inconjunction with the 5G Technology Forum (5GTF). 3GPP Long TermEvolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that useE-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP). cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies. For clarity, while aspects may be describedherein using terminology commonly associated with 3G and/or 4G wirelesstechnologies, aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

Example Wireless Communications System

FIG. 1 illustrates an example wireless network 100 in which aspects ofthe present disclosure may be performed. For example, the wirelessnetwork may be a new radio (NR) or 5G network. BS 110 may receive, fromthe UE 120, channel quality indicator (CQI) designed for URLLC asfurther described herein with respect to the operations depicted inFIGS. 8 and 9.

As illustrated in FIG. 1, the wireless network 100 may include a numberof BSs 110 and other network entities. A BS may be a station thatcommunicates with UEs. Each BS 110 may provide communication coveragefor a particular geographic area. In 3GPP, the term “cell” can refer toa coverage area of a Node B and/or a Node B subsystem serving thiscoverage area, depending on the context in which the term is used. In NRsystems, the term “cell” and gNB, Node B, 5G NB, AP, NR BS, NR BS, orTRP may be interchangeable. In some examples, a cell may not necessarilybe stationary, and the geographic area of the cell may move according tothe location of a mobile base station. In some examples, the basestations may be interconnected to one another and/or to one or moreother base stations or network nodes (not shown) in the wireless network100 through various types of backhaul interfaces such as a directphysical connection, a virtual network, or the like using any suitabletransport network.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular radioaccess technology (RAT) and may operate on one or more frequencies. ARAT may also be referred to as a radio technology, an air interface,etc. A frequency may also be referred to as a carrier, a frequencychannel, etc. Each frequency may support a single RAT in a givengeographic area in order to avoid interference between wireless networksof different RATs. In some cases, NR or 5G RAT networks may be deployed.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a Closed Subscriber Group (CSG), UEs for users in the home,etc.). A BS for a macro cell may be referred to as a macro BS. A BS fora pico cell may be referred to as a pico BS. A BS for a femto cell maybe referred to as a femto BS or a home BS. In the example shown in FIG.1, the BSs 110 a, 110 b and 110 c may be macro BSs for the macro cells102 a, 102 b and 102 c, respectively. The BS 110 x may be a pico BS fora pico cell 102 x. The BSs 110 y and 110 z may be femto BS for the femtocells 102 y and 102 z, respectively. A BS may support one or multiple(e.g., three) cells.

The wireless network 100 may also include relay stations. A relaystation is a station that receives a transmission of data and/or otherinformation from an upstream station (e.g., a BS or a UE) and sends atransmission of the data and/or other information to a downstreamstation (e.g., a UE or a BS). A relay station may also be a UE thatrelays transmissions for other UEs. In the example shown in FIG. 1, arelay station 110 r may communicate with the BS 110 a and a UE 120 r inorder to facilitate communication between the BS 110 a and the UE 120 r.A relay station may also be referred to as a relay BS, a relay, etc.

The wireless network 100 may be a heterogeneous network that includesBSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc.These different types of BSs may have different transmit power levels,different coverage areas, and different impact on interference in thewireless network 100. For example, a macro BS may have a high transmitpower level (e.g., 20 Watts) whereas pico BS, femto BS, and relays mayhave a lower transmit power level (e.g., 1 Watt).

The wireless network 100 may support synchronous or asynchronousoperation. For synchronous operation, the BSs may have similar frametiming, and transmissions from different BSs may be approximatelyaligned in time. For asynchronous operation, the BSs may have differentframe timing, and transmissions from different BSs may not be aligned intime. The techniques described herein may be used for both synchronousand asynchronous operation.

A network controller 130 may couple to a set of BSs and providecoordination and control for these BSs. The network controller 130 maycommunicate with the BSs 110 via a backhaul. The BSs 110 may alsocommunicate with one another, e.g., directly or indirectly via wirelessor wireline backhaul.

The UEs 120 (e.g., 120 x, 120 y, etc.) may be dispersed throughout thewireless network 100, and each UE may be stationary or mobile. A UE mayalso be referred to as a mobile station, a terminal, an access terminal,a subscriber unit, a station, a Customer Premises Equipment (CPE), acellular phone, a smart phone, a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, alaptop computer, a cordless phone, a wireless local loop (WLL) station,a tablet, a camera, a gaming device, a netbook, a smartbook, anultrabook, a medical device or medical equipment, a biometricsensor/device, a wearable device such as a smart watch, smart clothing,smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, asmart bracelet, etc.), an entertainment device (e.g., a music device, avideo device, a satellite radio, etc.), a vehicular component or sensor,a smart meter/sensor, industrial manufacturing equipment, a globalpositioning system device, or any other suitable device that isconfigured to communicate via a wireless or wired medium. Some UEs maybe considered evolved or machine-type communication (MTC) devices orevolved MTC (eMTC) devices. MTC and eMTC UEs include, for example,robots, drones, remote devices, sensors, meters, monitors, locationtags, etc., that may communicate with a BS, another device (e.g., remotedevice), or some other entity. A wireless node may provide, for example,connectivity for or to a network (e.g., a wide area network such asInternet or a cellular network) via a wired or wireless communicationlink. Some UEs may be considered Internet-of-Things (IoT) devices.

In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving BS, which is a BS designated toserve the UE on the downlink and/or uplink. A finely dashed line withdouble arrows indicates interfering transmissions between a UE and a BS.

Certain wireless networks (e.g., LTE) utilize orthogonal frequencydivision multiplexing (OFDM) on the downlink and single-carrierfrequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDMpartition the system bandwidth into multiple (K) orthogonal subcarriers,which are also commonly referred to as tones, bins, etc. Each subcarriermay be modulated with data. In general, modulation symbols are sent inthe frequency domain with OFDM and in the time domain with SC-FDM. Thespacing between adjacent subcarriers may be fixed, and the total numberof subcarriers (K) may be dependent on the system bandwidth. Forexample, the spacing of the subcarriers may be 15 kHz and the minimumresource allocation (called a ‘resource block’) may be 12 subcarriers(or 180 kHz). Consequently, the nominal FFT size may be equal to 128,256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10 or 20megahertz (MHz), respectively. The system bandwidth may also bepartitioned into subbands. For example, a subband may cover 1.08 MHz(i.e., 6 resource blocks), and there may be 1, 2, 4, 8 or 16 subbandsfor system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communications systems, such as NR.

NR may utilize OFDM with a CP on the uplink and downlink and includesupport for half-duplex operation using TDD. A single component carrierbandwidth of 100 MHz may be supported. NR resource blocks may span 12sub-carriers with a subcarrier bandwidth of 75 kHz over a 0.1 msduration. Each radio frame may consist of 50 subframes with a length of10 ms. Consequently, each subframe may have a length of 0.2 ms. Eachsubframe may indicate a link direction (i.e., DL or UL) for datatransmission and the link direction for each subframe may be dynamicallyswitched. Each subframe may include DL/UL data as well as DL/UL controldata. UL and DL subframes for NR may be as described in more detailbelow with respect to FIGS. 6 and 7. For certain NR networks, such aseMBB and/or URLLC, each subframe may include a subcarrier including upto 4 slots. A slot may be include to 14 minislots and up to 14 OFDMsymbols. A minislot may include one or more OFDM symbols. OFDM symbolsin a slot can be classified as downlink, flexible (i.e., downlink oruplink), or uplink. Beamforming may be supported and beam direction maybe dynamically configured. MIMO transmissions with precoding may also besupported. MIMO configurations in the DL may support up to 8 transmitantennas with multi-layer DL transmissions up to 8 streams and up to 2streams per UE. Multi-layer transmissions with up to 2 streams per UEmay be supported. Aggregation of multiple cells may be supported with upto 8 serving cells. Alternatively, NR may support a different airinterface, other than an OFDM-based. NR networks may include entitiessuch CUs and/or DUs.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. Within the present disclosure, as discussed further below,the scheduling entity may be responsible for scheduling, assigning,reconfiguring, and releasing resources for one or more subordinateentities. That is, for scheduled communication, subordinate entitiesutilize resources allocated by the scheduling entity. Base stations arenot the only entities that may function as a scheduling entity. That is,in some examples, a UE may function as a scheduling entity, schedulingresources for one or more subordinate entities (e.g., one or more otherUEs). In this example, the UE is functioning as a scheduling entity, andother UEs utilize resources scheduled by the UE for wirelesscommunication. A UE may function as a scheduling entity in apeer-to-peer (P2P) network, and/or in a mesh network. In a mesh networkexample, UEs may optionally communicate directly with one another inaddition to communicating with the scheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

As noted above, a RAN may include a CU and DUs. A NR BS (e.g., gNB, 5GNB, NB, TRP, AP) may correspond to one or multiple BSs. NR cells can beconfigured as access cells (ACells) or data only cells (DCells). Forexample, the RAN (e.g., a central unit or distributed unit) canconfigure the cells. DCells may be cells used for carrier aggregation ordual connectivity, but not used for initial access, cellselection/reselection, or handover. In some cases DCells may nottransmit synchronization signals—in some case cases DCells may transmitSS. NR BSs may transmit downlink signals to UEs indicating the celltype. Based on the cell type indication, the UE may communicate with theNR BS. For example, the UE may determine NR BSs to consider for cellselection, access, handover, and/or measurement based on the indicatedcell type.

FIG. 2 illustrates an example logical architecture of a distributedradio access network (RAN) 200, which may be implemented in the wirelesscommunication system illustrated in FIG. 1. A 5G access node 206 mayinclude an access node controller (ANC) 202. The ANC may be a centralunit (CU) of the distributed RAN 200. The backhaul interface to the nextgeneration core network (NG-CN) 204 may terminate at the ANC. Thebackhaul interface to neighboring next generation access nodes (NG-ANs)may terminate at the ANC. The ANC may include one or more TRPs 208(which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs, orsome other term). As described above, a TRP may be used interchangeablywith “cell.”

The TRPs 208 may be a DU. The TRPs may be connected to one ANC (ANC 202)or more than one ANC (not illustrated). For example, for RAN sharing,radio as a service (RaaS), and service specific AND deployments, the TRPmay be connected to more than one ANC. A TRP may include one or moreantenna ports. The TRPs may be configured to individually (e.g., dynamicselection) or jointly (e.g., joint transmission) serve traffic to a UE.

The local architecture 200 may be used to illustrate fronthauldefinition. The architecture may be defined that support fronthaulingsolutions across different deployment types. For example, thearchitecture may be based on transmit network capabilities (e.g.,bandwidth, latency, and/or jitter).

The architecture may share features and/or components with LTE.According to aspects, the next generation AN (NG-AN) 210 may supportdual connectivity with NR. The NG-AN may share a common fronthaul forLTE and NR.

The architecture may enable cooperation between and among TRPs 208. Forexample, cooperation may be preset within a TRP and/or across TRPs viathe ANC 202. According to aspects, no inter-TRP interface may beneeded/present.

According to aspects, a dynamic configuration of split logical functionsmay be present within the architecture 200. As will be described in moredetail with reference to FIG. 5, the Radio Resource Control (RRC) layer,Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC)layer, Medium Access Control (MAC) layer, and a Physical (PHY) layersmay be adaptably placed at the DU or CU (e.g., TRP or ANC,respectively). According to certain aspects, a BS may include a centralunit (CU) (e.g., ANC 202) and/or one or more distributed units (e.g.,one or more TRPs 208).

FIG. 3 illustrates an example physical architecture of a distributed RAN300, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 302 may host core network functions. The C-CU may becentrally deployed. C-CU functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 304 may host one or more ANC functions.Optionally, the C-RU may host core network functions locally. The C-RUmay have distributed deployment. The C-RU may be closer to the networkedge.

A DU 306 may host one or more TRPs (edge node (EN), an edge unit (EU), aradio head (RH), a smart radio head (SRH), or the like). The DU may belocated at edges of the network with radio frequency (RF) functionality.

FIG. 4 illustrates example components of the BS 110 and UE 120illustrated in FIG. 1, which may be used to implement aspects of thepresent disclosure. One or more components of the BS 110 and UE 120 maybe used to practice aspects of the present disclosure. For example,antennas 452, Tx/Rx 222, processors 466, 458, 464, and/orcontroller/processor 480 of the UE 120 and/or antennas 434, processors420, 430, 438, and/or controller/processor 440 of the BS 110 may be usedto perform the operations described herein and illustrated withreference to FIGS. 8 and 9.

FIG. 4 shows a block diagram of a design of a BS 110 and a UE 120, whichmay be one of the BSs and one of the UEs in FIG. 1. For a restrictedassociation scenario, the base station 110 may be the macro BS 110 c inFIG. 1, and the UE 120 may be the UE 120 y. The base station 110 mayalso be a base station of some other type. The base station 110 may beequipped with antennas 434 a through 434 t, and the UE 120 may beequipped with antennas 452 a through 452 r.

At the base station 110, a transmit processor 420 may receive data froma data source 412 and control information from a controller/processor440. The control information may be for the Physical Broadcast Channel(PBCH), Physical Control Format Indicator Channel (PCFICH), PhysicalHybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel(PDCCH), etc. The data may be for the Physical Downlink Shared Channel(PDSCH), etc. The processor 420 may process (e.g., encode and symbolmap) the data and control information to obtain data symbols and controlsymbols, respectively. The processor 420 may also generate referencesymbols, e.g., for the PSS, SSS, and cell-specific reference signal. Atransmit (TX) multiple-input multiple-output (MIMO) processor 430 mayperform spatial processing (e.g., precoding) on the data symbols, thecontrol symbols, and/or the reference symbols, if applicable, and mayprovide output symbol streams to the modulators (MODs) 432 a through 432t. Each modulator 432 may process a respective output symbol stream(e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator432 may further process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a downlink signal.Downlink signals from modulators 432 a through 432 t may be transmittedvia the antennas 434 a through 434 t, respectively.

At the UE 120, the antennas 452 a through 452 r may receive the downlinksignals from the base station 110 and may provide received signals tothe demodulators (DEMODs) 454 a through 454 r, respectively. Eachdemodulator 454 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 454 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 456 may obtainreceived symbols from all the demodulators 454 a through 454 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 458 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 120 to a data sink 460, and provide decoded control informationto a controller/processor 480.

On the uplink, at the UE 120, a transmit processor 464 may receive andprocess data (e.g., for the Physical Uplink Shared Channel (PUSCH)) froma data source 462 and control information (e.g., for the Physical UplinkControl Channel (PUCCH) from the controller/processor 480. The transmitprocessor 464 may also generate reference symbols for a referencesignal. The symbols from the transmit processor 464 may be precoded by aTX MIMO processor 466 if applicable, further processed by thedemodulators 454 a through 454 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 110. At the BS 110, the uplink signalsfrom the UE 120 may be received by the antennas 434, processed by themodulators 432, detected by a MIMO detector 436 if applicable, andfurther processed by a receive processor 438 to obtain decoded data andcontrol information sent by the UE 120. The receive processor 438 mayprovide the decoded data to a data sink 439 and the decoded controlinformation to the controller/processor 440.

The controllers/processors 440 and 480 may direct the operation at thebase station 110 and the UE 120, respectively. The processor 440 and/orother processors and modules at the BS 110 may perform or direct, e.g.,the execution of the functional blocks illustrated in FIG. 8 and/orother processes for the techniques described herein. The processor 480and/or other processors and modules at the UE 120 may also perform ordirect, e.g., the execution of the functional blocks illustrated in FIG.9 and/or other processes for the techniques described herein. Thememories 442 and 482 may store data and program codes for the BS 110 andthe UE 120, respectively. A scheduler 444 may schedule UEs for datatransmission on the downlink and/or uplink.

FIG. 5 illustrates a diagram 500 showing examples for implementing acommunications protocol stack, according to aspects of the presentdisclosure. The illustrated communications protocol stacks may beimplemented by devices operating in a in a 5G system (e.g., a systemthat supports uplink-based mobility). Diagram 500 illustrates acommunications protocol stack including a Radio Resource Control (RRC)layer 510, a Packet Data Convergence Protocol (PDCP) layer 515, a RadioLink Control (RLC) layer 520, a Medium Access Control (MAC) layer 525,and a Physical (PHY) layer 530. In various examples the layers of aprotocol stack may be implemented as separate modules of software,portions of a processor or ASIC, portions of non-collocated devicesconnected by a communications link, or various combinations thereof.Collocated and non-collocated implementations may be used, for example,in a protocol stack for a network access device (e.g., ANs, CUs, and/orDUs) or a UE.

A first option 505-a shows a split implementation of a protocol stack,in which implementation of the protocol stack is split between acentralized network access device (e.g., an ANC 202 in FIG. 2) anddistributed network access device (e.g., DU 208 in FIG. 2). In the firstoption 505-a, an RRC layer 510 and a PDCP layer 515 may be implementedby the central unit, and an RLC layer 520, a MAC layer 525, and a PHYlayer 530 may be implemented by the DU. In various examples the CU andthe DU may be collocated or non-collocated. The first option 505-a maybe useful in a macro cell, micro cell, or pico cell deployment.

A second option 505-b shows a unified implementation of a protocolstack, in which the protocol stack is implemented in a single networkaccess device (e.g., access node (AN), new radio base station (NR BS), anew radio Node-B (NR NB), a network node (NN), or the like). In thesecond option, the RRC layer 510, the PDCP layer 515, the RLC layer 520,the MAC layer 525, and the PHY layer 530 may each be implemented by theAN. The second option 505-b may be useful in a femto cell deployment.

Regardless of whether a network access device implements part or all ofa protocol stack, a UE may implement an entire protocol stack (e.g., theRRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525,and the PHY layer 530).

FIG. 6 is a diagram 600 showing an example of a DL-centric subframe. TheDL-centric subframe may include a control portion 602. The controlportion 602 may exist in the initial or beginning portion of theDL-centric subframe. The control portion 602 may include variousscheduling information and/or control information corresponding tovarious portions of the DL-centric subframe. In some configurations, thecontrol portion 602 may be a physical DL control channel (PDCCH), asindicated in FIG. 6. The DL-centric subframe may also include a DL dataportion 604. The DL data portion 604 may sometimes be referred to as thepayload of the DL-centric subframe. The DL data portion 604 may includethe communication resources utilized to communicate DL data from thescheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE).In some configurations, the DL data portion 604 may be a physical DLshared channel (PDSCH).

The DL-centric subframe may also include a common UL portion 606. Thecommon UL portion 606 may sometimes be referred to as an UL burst, acommon UL burst, and/or various other suitable terms. The common ULportion 606 may include feedback information corresponding to variousother portions of the DL-centric subframe. For example, the common ULportion 606 may include feedback information corresponding to thecontrol portion 602. Non-limiting examples of feedback information mayinclude an ACK signal, a NACK signal, a HARQ indicator, and/or variousother suitable types of information. The common UL portion 606 mayinclude additional or alternative information, such as informationpertaining to random access channel (RACH) procedures, schedulingrequests (SRs), and various other suitable types of information. Asillustrated in FIG. 6, the end of the DL data portion 604 may beseparated in time from the beginning of the common UL portion 606. Thistime separation may sometimes be referred to as a gap, a guard period, aguard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the subordinate entity (e.g., UE)) to UL communication(e.g., transmission by the subordinate entity (e.g., UE)). One ofordinary skill in the art will understand that the foregoing is merelyone example of a DL-centric subframe and alternative structures havingsimilar features may exist without necessarily deviating from theaspects described herein.

FIG. 7 is a diagram 700 showing an example of an UL-centric subframe.The UL-centric subframe may include a control portion 702. The controlportion 702 may exist in the initial or beginning portion of theUL-centric subframe. The control portion 702 in FIG. 7 may be similar tothe control portion 602 described above with reference to FIG. 6. TheUL-centric subframe may also include an UL data portion 704. The UL dataportion 704 may sometimes be referred to as the payload of theUL-centric subframe. The UL portion may refer to the communicationresources utilized to communicate UL data from the subordinate entity(e.g., UE) to the scheduling entity (e.g., UE or BS). In someconfigurations, the control portion 702 may be a physical DL controlchannel (PDCCH).

As illustrated in FIG. 7, the end of the control portion 702 may beseparated in time from the beginning of the UL data portion 704. Thistime separation may sometimes be referred to as a gap, guard period,guard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the scheduling entity) to UL communication (e.g.,transmission by the scheduling entity). The UL-centric subframe may alsoinclude a common UL portion 706. The common UL portion 706 in FIG. 7 maybe similar to the common UL portion 606 described above with referenceto FIG. 6. The common UL portion 706 may additional or alternativeinclude information pertaining to channel quality indicator (CQI),sounding reference signals (SRSs), and various other suitable types ofinformation. One of ordinary skill in the art will understand that theforegoing is merely one example of an UL-centric subframe andalternative structures having similar features may exist withoutnecessarily deviating from the aspects described herein. In one example,a frame may include both UL centric subframes and DL centric subframes.In this example, the ratio of UL centric subframes to DL subframes in aframe may be dynamically adjusted based on the amount of UL data and theamount of DL data that are transmitted. For example, if there is more ULdata, then the ratio of UL centric subframes to DL subframes may beincreased. Conversely, if there is more DL data, then the ratio of ULcentric subframes to DL subframes may be decreased.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet-of-Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

A UE may operate in various radio resource configurations, including aconfiguration associated with transmitting pilots using a dedicated setof resources (e.g., a radio resource control (RRC) dedicated state,etc.) or a configuration associated with transmitting pilots using acommon set of resources (e.g., an RRC common state, etc.). Whenoperating in the RRC dedicated state, the UE may select a dedicated setof resources for transmitting a pilot signal to a network. Whenoperating in the RRC common state, the UE may select a common set ofresources for transmitting a pilot signal to the network. In eithercase, a pilot signal transmitted by the UE may be received by one ormore network access devices, such as an AN, or a DU, or portionsthereof. Each receiving network access device may be configured toreceive and measure pilot signals transmitted on the common set ofresources, and also receive and measure pilot signals transmitted ondedicated sets of resources allocated to the UEs for which the networkaccess device is a member of a monitoring set of network access devicesfor the UE. One or more of the receiving network access devices, or a CUto which receiving network access device(s) transmit the measurements ofthe pilot signals, may use the measurements to identify serving cellsfor the UEs, or to initiate a change of serving cell for one or more ofthe UEs.

A wireless system may support various transmission modes. Thesetransmission modes may include, for example, single-user multiple-inputmultiple-output (SU-MIMO), multi-user MIMO (MU-MIMO), coordinatedmulti-point (CoMP), enhanced mobile broadband (eMBB), ultra-reliable lowlatency communications (URLLC), or a modulation and coding scheme (MCS).

In wireless communications, channel state information (CSI) may refer toknown channel properties of a communication link. The CSI may representthe combined effects of, for example, scattering, fading, and powerdecay with distance between a transmitter and receiver. Channelestimation may be performed to determine these effects on the channel.CSI may be used to adapt transmissions based on the current channelconditions, which is useful for achieving reliable communication, inparticular, with high data rates in multi-antenna systems. CSI istypically estimated at the receiver, quantized, and fed back to thetransmitter to support the various transmission modes. For instance, aBS may receive the CSI feedback from a UE and determines a MCS fortransmissions to the UE based on the CSI feedback.

In general, CSI may include any information that may be used by atransmitter to determine which transmission mode is suitable to transmitdata to a receiver. CSI may include channel quality indicator (CQI),rank indicator (RI), precoding matrix indicator (PMI), etc. CQI may beindicative of the quality of a communication channel from thetransmitter to the receiver. RI may be indicative of the number of datastreams to transmit simultaneously to the receiver. Each data stream maycorrespond to a codeword, a data packet, a transport block, a spatialchannel, etc. PMI may be indicative of a precoding matrix to use tospatially process (or precode) data prior to transmission to thereceiver. A precoding matrix may correspond to a spatial beam that maysteer data transmission toward the receiver and/or away from otherreceivers.

MCS and CQI Design for High Reliability

Certain communication systems (e.g., NR) maintain ultra-reliable lowlatency communication (URLLC) which provides requirements for latencyand reliability. For example, URLLC may provide an end-to-end latency of10 milliseconds and block error ratio (BLER) of 10⁻⁵ within 1millisecond. Other communication services (e.g., eMBB) utilize MCS/CQItables (e.g., Table 1 shown below) that have coarse granularity in thelower spectral efficiency (SE) region (e.g, SE<1) and are not suitablefor reaching the reliability and latency requirements of URLLC. Forexample, the MCS and SE entries used from Table 1 may result in highlyinefficient resource allocation for URLLC due to lack of granularity inthe low SE region (e.g., SE<1). Additional entries may not be added tothe MCS/CQI table due to signaling overhead limitations.

TABLE 1 Example CQI Table CQI index MCS code rate × 1024 SE 0 out ofrange 1 QPSK 78 0.1523 2 QPSK 120 0.2344 3 QPSK 193 0.3770 4 QPSK 3080.6016 5 QPSK 449 0.8770 6 QPSK 602 1.1758 7 16QAM 378 1.4766 8 16QAM490 1.9141 9 16QAM 616 2.4063 10 64QAM 466 2.7305 11 64QAM 567 3.3223 1264QAM 666 3.9023 13 64QAM 772 4.5234 14 64QAM 873 5.1152 15 64QAM 9485.5547

QPSK refers to quadrature phase shift keying having a modulation order(Q_(m)) (e.g., the number of bits conveyed by a symbol) of 2; 16QAMrefers to a quadrature amplitude modulation (QAM) scheme having amodulation order of 4; and 64QAM refers to a QAM scheme having amodulation order of 6.

The RAN and UE may employ CSI feedback that is designed to providehighly reliable transmissions such as satisfying the reliability and/orlatency requirements implemented for URLLC (e.g., a BLER of 10⁻⁵ and anend-to-end latency of 10 milliseconds). For instance, a set of CQIvalues providing finer granularity at lower SE values for a given MCSmay facilitate satisfying BLERs below 10⁻¹. This is due to the fact thata lower BLER target favors lower SE values. When targeting lower BLERvalues, a lower MCS value (e.g., QPSK) for the initial transmission mayalso achieve the lower target BLER at a lower latency. Aspects presentedherein provide techniques for providing and utilizing an MCS tableand/or an CQI table (MCS/CQI tables) optimized for URLLC services.

FIG. 8 is a flow diagram illustrating example operations 800 that may beperformed, for example, by a base station (e.g., BS 110 of FIG. 1)and/or radio access network, for implementing MCS/CQI related-parametersfor high reliability, in accordance with certain aspects of the presentdisclosure. Operations 800 may be implemented as software componentsthat are executed and run on one or more processors (e.g., processor 440of FIG. 4). Further, the transmission and reception of signals by the BSin operations 800 may be enabled, for example, by one or more antennas(e.g., antenna(s) 434 of FIG. 4). In certain aspects, the transmissionand/or reception of signals by the BS may be implemented via a businterface of one or more processors (e.g., processor 440) obtainingand/or outputting signals.

Operations 800 may begin, at 802, by the BS receiving a channel qualityindicator (CQI) from a user equipment (UE) (e.g., a UE configured forURLLC services). At 804, the BS retrieves parameters from a modulationand coding scheme (MCS) table using the CQI, wherein the table hasentries corresponding to different spectral efficiency (SE) valuesselected to allow the BS to efficiently allocate resources at low SEvalues to achieve at least a target BLER (e.g., a BLER from 10⁻² to 10⁻⁵or less). At 806, the BS sends a transmission to the UE based on theretrieved parameters.

In certain aspects, the MCS table may include entries that correspond toat least one of a modulation order, a transport block size, a targetcode rate, and a spectral efficiency value. That is, the parametersretrieved and/or determined by the BS may include the modulation order,target code rate, the transport block size, and/or the spectralefficiency to derive the size of the resources allocated to the UE, andthe BS may use these parameters to form the signal transmitted to the UEat 806. For example, the BS may select a MCS based on the modulationorder and allocate resources for the transmission based on the transportblock size which may or may not be derived from the target code rate andspectral efficiency value.

FIG. 9 is a flow diagram illustrating example operations 900 that may beperformed, for example, by a UE (e.g., UE 120), for implementing MCS/CQIrelated-parameters for high reliability, in accordance with certainaspects of the present disclosure. Operations 900 may be implemented assoftware components that are executed and run on one or more processors(e.g., processor 480 of FIG. 4). Further, the transmission and receptionof signals by the UE in operations 900 may be enabled, for example, byone or more antennas (e.g., antenna(s) 452 of FIG. 4). In certainaspects, the transmission and/or reception of signals by the UE may beimplemented via a bus interface of one or more processors (e.g.,processor 480) obtaining and/or outputting signals.

Operations 900 may begin, at 902, by the UE determining a channelquality indicator (CQI) based on measurement of signals from a basestation. At 904, the UE determines a rank indicator (RI) value. At 906,the UE signals the CQI to the base station, wherein the CQI value isused to indicate the RI value.

In certain aspects, the UE may also transmit its capabilities, to theRAN, indicating that the UE is configured to support the MCS/CQI tablesassociated with URLLC services as described herein. The capabilities ofthe UE to support the MCS/CQI tables associated with URLLC services maybe included in a flag (e.g., a single bit Boolean) and transmitted tothe RAN via radio resource control signaling. The RAN may receive thecapabilities of the UE and allocate URLLC resources to the UE based onthe associated MCS/CQI tables according to operations 800 as describedherein.

In certain aspects, the CQI table used by the UE to select the CQI mayhave a fixed set of CQI entries. For instance, the CQI determined by theUE may be a 4-bit entry corresponding to a specific MCS and SEcombination at a target code rate of a transport block size. The CQItable may have 16 CQI entries including, for example, 15 entries thatindicate different MCS and SE combinations and one CQI entry forindicating the UE is out of range of the BS's transmissions similar toTable 1.

The UE may have CQI/MCS tables associated with different target BLERs.Each table may have entries corresponding to different spectralefficiency (SE) values selected to allow the BS to efficiently allocateresources at SE values to achieve at least a target BLER. For instance,one or more CQI/MCS tables may be associated with a BLER of 0.1, whereasa different CQI/MCS table may be associated with a BLER of 10⁻⁵. The UEmay select the particular CQI/MCS table depending on the target BLERconfigured for the UE.

In certain aspects, the SE values of the MCS/CQI tables are selected sothat a difference in allocated resource blocks (RBs) between adjacententries in the MCS table and/or the CQI table is within a thresholdlimit. For example, FIG. 10 is an exemplary graph of the number ofresource blocks (RBs) allocated with respect to SE, in accordance withcertain aspects of the present disclosure. As shown, curve 1002 is afunction of resource block allocations with respect to SE. In thisexample, the curve 1002 represents the RB allocations required totransmit a transport block of a set size at a given SE value with a416-bit payload to achieve a target BLER (e.g., a BLER not exceeding10⁻⁵). The intersections of the dashed lines 1010 and the curve 1002form the SE values for MCS/CQI entries of the MCS/CQI table. Forexample, the intersection of line 1012 and the curve 1002 provides an SEvalue of about 0.3 with about 104 RBs. This intersection may provide theminimum SE value for the MCS/CQI entries, whereas the intersection ofline 1014 and curve 1002 may provide the maximum SE value of the MCS/CQIentries. The difference between the intersections along the curve 1002may be within a threshold limit. In this example, the RB allocationspacing (i.e., the spacing between lines 1010) is evenly distributedbetween the minimum SE value (1012) and the maximum SE value (1014). Incertain aspects, the spacing between RB allocation values may beabsolute (fixed), relative, or arbitrary.

In certain aspects, different combinations of a coding rate, modulationorder (i.e., MCS), and rank may be used to reach the SE values alongcurve 1002. In other words, the coding rate, MCS, and rank may beselected to yield the SE values along the curve 1002 for the givenpayload, transport block size, and target BLER. These settings forcoding rate, MCS, rank, and SE value may be preset to provide a CQItable similar to Table 1 and an MCS table for implementing operations800 and 900.

FIG. 10 also demonstrates that at high SE values (e.g., SE>1) a changein SE has a minor impact on the allocation. That is, the number ofresource block allocations approaches a limit as the spectral efficiencyincreases. Therefore, a coarser MCS/CQI granularity at high SE valueswill not have a significant impact on URLLC, which is designed to targetlow BLER.

In certain aspects, the SE values are selected so that steps in signalto noise ratio (SNR) at the target BLER are smaller for low SE values.For example, FIG. 11 shows a graph of a performance-related parameter(e.g., SNR) with respect to spectral efficiency, in accordance withcertain aspect of the present disclosure. As shown, curve 1102 is afunction of signal-to-noise ratio (SNR) in decibels with respect tospectral efficiency determined to achieve a target BLER (e.g., a BLER of10⁻⁵). Similar to the technique described with respect to FIG. 10, theSE values for the MCS/CQI entries may be selected based on theintersections of curve 1102 and horizontal lines 1110. In this example,the minimum SE value at line 1112 is about 0.4 for an SNR of about −3.5dB, and the maximum SE value at line 1114 is about 1.6 for an SNR ofabout 6 dB. The spacing between lines 1110 may be smaller for low SEvalues (e.g, SE<1) than the spacing for high SE values (e.g., SE>1). Incertain aspects, the spacing between SNR values for lines 1110 may beabsolute (fixed), relative, or arbitrary. Similar to FIG. 10, differentcombinations of a coding rate, modulation order (i.e., MCS), and rankmay be used to reach the SE values along curve 1102. In certain aspects,the performance-related parameter used to select SE values may includeat least one of a signal-to-noise ratio (SNR),signal-to-interference-plus-noise ratio (SINR), energy per bit to noisepower spectral density ratio (E_(b)/N₀), received signal strengthindication (RSSI), reference signals received power (RSRP), referencesignals received quality (RSRQ), or the like.

In certain aspects, the set of SE values are determined based on aninterpolation of SE values from an MCS table used for UEs configured tosupport a different service type (e.g., eMBB) than the URLLC UE. Forexample, the set of SE values may be determined based on aninterpolation of SE values from a MCS/CQI table used for UEs configuredto support eMBB services (e.g., Table 1 shown above).

In certain aspects, the set of SE values are determined based on aninterpolation of performance metrics from an MCS table used for UEsconfigured for a different type than the URLLC UE. For example, the setof SE values may be determined based on an interpolation of SE valuesfor the performance at a target BLER starting from a MCS/CQI table usedfor eMBB UEs (e.g., Table 1 shown above). The performance metric usedfor interpolation may include at least one of a target BLER,signal-to-noise ratio (SNR), received signal strength indication (RSSI),signal-to-interference-plus-noise ratio (SINR), energy per bit to noisepower spectral density ratio (E_(b)/N₀), received signal strengthindication (RSSI), reference signals received power (RSRP), referencesignals received quality (RSRQ), or the like.

In certain aspects, reducing the overhead of uplink control signaling(e.g., uplink control information including CSI feedback) may enablereaching the target BLER and/or latency requirements implemented forURLLC. For instance, reducing the CQI overhead may improve UCI decodingperformance at the BS, which in turn reduces the latency encountered atthe BS. This indirectly helps the UE achieve the target BLER Aspreviously discussed, the CSI feedback may include CQI and a rankindicator (RI), which is a multi-bit value and its width depends on thereport type and number of antenna ports of the UE. For URLLC, with thelower BLER targets, some rank and CQI combinations are unlikely to beused by the UE. For instance, the UE is unlikely to use a high RI andCQI values for URLLC. This is because the URLLC UE will be allocatedmore reliable resources and MCSs.

In certain aspects, UCI overhead may be reduced by the BS determining arank indicator (RI) value, based at least in part on the CQI value. Thatis, the BS and UE are programmed in advance such that an RI valuecorresponds to a specific CQI value, allowing the UE to omit the RI fromthe UCI. For example, a first set of one or more CQI values maps to afirst set of RI values, and a second set of one or more CQI values mapsto a second set of RI values. In certain aspects, the first set of CQIvalues may include CQI values less than or equal to a threshold value(e.g., CQI=4), and the second set of CQI values may include CQI valuesgreater than the threshold value. In certain aspects, the CQI value maydetermine a number of bits used to convey the RI value.

FIG. 12 illustrates a wireless communications device 1200 that mayinclude various components (e.g., corresponding to means-plus-functioncomponents) configured to perform operations for the techniquesdisclosed herein, such as the operations illustrated in one or more ofFIGS. 8 and 9. The communications device 1200 includes a processingsystem 1202 coupled to a transceiver 1210. The transceiver 1210 isconfigured to transmit and receive signals for the communications device1200 via an antenna 1212, such as the various signals described herein.The processing system 1202 may be configured to perform processingfunctions for the communications device 1200, including processingsignals received and/or to be transmitted by the communications device1200.

The processing system 1202 includes one or more processors 1204 coupledto a computer-readable medium/memory 1206 via a bus 1208. In certainaspects, the computer-readable medium/memory 1206 is configured to storecomputer-executable instructions that when executed by processor 1204,cause the processor 1204 to perform the operations illustrated in one ormore of FIGS. 8 and 9, or other operations for performing the varioustechniques discussed herein.

In certain aspects, the processing system 1202 further includes areceive component 1214 for performing the receiving operationsillustrated in one or more of FIGS. 8 and 9. Additionally, theprocessing system 1202 includes a transmit component 1216 for performingthe transmitting operations illustrated in one or more of FIGS. 8 and 9.Further, the processing system 1202 includes a performing component 1218for performing the performing operations illustrated in one or more ofFIGS. 8 and 9. Also, the processing system 1202 includes a determiningcomponent 1020 for performing the determining operations illustrated inone or more of FIGS. 8 and 9. The receive component 1214, transmitcomponent 1216, performing component 1218, and determining component1220 may be coupled to the processor 1204 via bus 1208. The processor1204 may obtain or output signals via the bus 1208 for performing theoperations illustrated in one or more of FIGS. 8 and 9. In certainaspects, the receive component 1214, transmit component 1216, performingcomponent 1218, and determining component 1220 may be hardware circuits.In certain aspects, the receive component 1214, transmit component 1216,performing component 1218, and determining component 1220 may besoftware components that are executed and run on processor 1204.

Techniques described herein provide advantages to URLLC systems. Toimprove the latency and reliability of URLLC systems, the RAN and UE mayuse an MCS table and/or a CQI table designed for a target BLERimplemented for URLLC. The UCI overhead may also be reduced by signalingthe RI value based at least in part on the CQI value as describedherein.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. § 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or, in the case of a method claim, theelement is recited using the phrase “step for.”

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering.

For example, means for transmitting (or means for outputting fortransmission) may comprise an antenna(s) 434 of the base station 110 orthe antenna(s) 452 of the user equipment 120 illustrated in FIG. 4.Means for receiving (or means for obtaining) may comprise an antenna(s)434 of the base station 110 or antenna(s) 452 of the user equipment 120illustrated in FIG. 4. Means for processing, means for obtaining, meansfor generating, means for selecting, means for decoding, or means fordetermining, may comprise a processing system, which may include one ormore processors, such as the MIMO detector 242, the TX MIMO processor430, the TX processor 420, and/or the controller 440 of the base station110 or the MIMO detector 456, the TX MIMO processor 466, the TXprocessor 464, and/or the controller 480 of the user equipment 120illustrated in FIG. 4.

In some cases, rather than actually transmitting a signal, a device mayhave an interface to output a signal for transmission (a means foroutputting). For example, a processor may output a signal, via a businterface, to a radio frequency (RF) front end for transmission.Similarly, rather than actually receiving a signal, a device may have aninterface to obtain a signal received from another device (a means forobtaining). For example, a processor may obtain (or receive) a signal,via a bus interface, from an RF front end for reception. In some cases,an interface to output a signal for transmission and an interface forobtaining a signal may be integrated as a single interface.

As used herein, the terms “transmitting” and “receiving” encompass awide variety of actions. For example, “transmitting” may includeoutputting (e.g., outputting a signal to be transmitted), signaling, andthe like. Also, “receiving” may include obtaining (e.g., obtaining asignal), accessing (e.g., accessing data in a memory), sampling (e.g.,sampling a signal), and the like.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in hardware, an example hardware configuration maycomprise a processing system in a wireless node. The processing systemmay be implemented with a bus architecture. The bus may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system and the overall design constraints.The bus may link together various circuits including a processor,machine-readable media, and a bus interface. The bus interface may beused to connect a network adapter, among other things, to the processingsystem via the bus. The network adapter may be used to implement thesignal processing functions of the PHY layer. In the case of a userequipment 120 (see FIG. 1), a user interface (e.g., keypad, display,mouse, joystick, etc.) may also be connected to the bus. The bus mayalso link various other circuits such as timing sources, peripherals,voltage regulators, power management circuits, and the like, which arewell known in the art, and therefore, will not be described any further.The processor may be implemented with one or more general-purpose and/orspecial-purpose processors. Examples include microprocessors,microcontrollers, DSP processors, and other circuitry that can executesoftware. Those skilled in the art will recognize how best to implementthe described functionality for the processing system depending on theparticular application and the overall design constraints imposed on theoverall system.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer-readable medium.Software shall be construed broadly to mean instructions, data, or anycombination thereof, whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. The processor may beresponsible for managing the bus and general processing, including theexecution of software modules stored on the machine-readable storagemedia. A computer-readable storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor. By way of example, the machine-readable mediamay include a transmission line, a carrier wave modulated by data,and/or a computer readable storage medium with instructions storedthereon separate from the wireless node, all of which may be accessed bythe processor through the bus interface. Alternatively, or in addition,the machine-readable media, or any portion thereof, may be integratedinto the processor, such as the case may be with cache and/or generalregister files. Examples of machine-readable storage media may include,by way of example, RAM (Random Access Memory), flash memory, ROM (ReadOnly Memory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product.

A software module may comprise a single instruction, or manyinstructions, and may be distributed over several different codesegments, among different programs, and across multiple storage media.The computer-readable media may comprise a number of software modules.The software modules include instructions that, when executed by anapparatus such as a processor, cause the processing system to performvarious functions. The software modules may include a transmissionmodule and a receiving module. Each software module may reside in asingle storage device or be distributed across multiple storage devices.By way of example, a software module may be loaded into RAM from a harddrive when a triggering event occurs. During execution of the softwaremodule, the processor may load some of the instructions into cache toincrease access speed. One or more cache lines may then be loaded into ageneral register file for execution by the processor. When referring tothe functionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

Also, any connection is properly termed a computer-readable medium. Forexample, if the software is transmitted from a website, server, or otherremote source using a coaxial cable, fiber optic cable, twisted pair,digital subscriber line (DSL), or wireless technologies such as infrared(IR), radio, and microwave, then the coaxial cable, fiber optic cable,twisted pair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. A method for wireless communication by a basestation (BS), comprising: receiving a channel quality indicator (CQI)from a user equipment (UE); retrieving parameters from a modulation andcoding scheme (MCS) table using the CQI, wherein the table has entriescorresponding to different spectral efficiency (SE) values selected toallow the BS to efficiently allocate resources at low SE values toachieve at least a target block error rate (BLER); and sending atransmission to the UE based on the retrieved parameters.
 2. The methodof claim 1, wherein the MCS table has an entry corresponding to aminimum SE value included in a CQI table used by the UE to select theCQI.
 3. The method of claim 1, wherein the SE values are selected sothat steps in signal to noise ratio (SNR) at the target BLER are smallerfor low SE values.
 4. The method of claim 1, wherein the SE values areselected so that a difference in allocated resource blocks (RBs) betweenadjacent entries in the MCS table is within a threshold limit.
 5. Themethod of claim 1, wherein: the UE is configured to support a service ofa first type; and the set of SE values are determined based on aninterpolation of SE values from an MCS table used for UEs configured tosupport a service of a second type.
 6. The method of claim 1, wherein:the UE is configured to support a service of a first type; and the setof SE values are determined based on an interpolation of performancemetrics from an MCS table used for UEs configured to support a serviceof a second type.
 7. The method of claim 1, further comprisingdetermining a rank indicator (RI) value, based at least in part on thereceived CQI.
 8. The method of claim 7, wherein: a first set of one ormore CQI values maps to a first set of RI values; and a second set ofone or more CQI values maps to a second set of RI values.
 9. The methodof claim 8, wherein: the first set of CQI values comprise CQI valuesless than or equal to a threshold value; and the second set of CQIvalues comprise CQI values greater than the threshold value.
 10. Themethod of claim 8, wherein the CQI value determines a number of bitsused to convey the RI value.
 11. A method for wireless communication bya user equipment (UE), comprising: determining a channel qualityindicator (CQI) based on measurement of signals from a base station;determining a rank indicator (RI) value; and signaling the CQI to thebase station, wherein the CQI value is used to indicate the RI value.12. The method of claim 11, wherein: a first set of one or more CQIvalues maps to a first set of RI values; and a second set of one or moreCQI values maps to a second set of RI values.
 13. The method of claim12, wherein: the first set of CQI values comprise CQI values less thanor equal to a threshold value; and the second set of CQI values compriseCQI values greater than the threshold value.
 14. The method of claim 11,wherein the CQI value determines a number of bits used to convey the RIvalue.
 15. An apparatus for wireless communication, comprising: aninterface configured to: obtain a channel quality indicator (CQI) from auser equipment (UE), and send a transmission to the UE based onretrieved parameters; and a processing system configured to retrieveparameters from a modulation and coding scheme (MCS) table using theCQI, wherein the table has entries corresponding to different spectralefficiency (SE) values selected to allow the BS to efficiently allocateresources at low SE values to achieve at least a target block error rate(BLER).
 16. An apparatus for wireless communication, comprising: aprocessing system configured to: determine a channel quality indicator(CQI) based on measurement of signals from a base station, and determinea rank indicator (RI) value; and an interface configured to signal theCQI to the base station, wherein the CQI value is used to indicate theRI value.
 17. An apparatus for wireless communication, comprising: meansfor receiving a channel quality indicator (CQI) from a user equipment(UE); means for retrieving parameters from a modulation and codingscheme (MCS) table using the CQI, wherein the table has entriescorresponding to different spectral efficiency (SE) values selected toallow the BS to efficiently allocate resources at low SE values toachieve at least a target block error rate (BLER); and means for sendinga transmission to the UE based on the retrieved parameters.
 18. Anapparatus for wireless communication, comprising: means for determininga channel quality indicator (CQI) based on measurement of signals from abase station; means for determining a rank indicator (RI) value; andmeans for signaling the CQI to the base station, wherein the CQI valueis used to indicate the RI value.
 19. A computer readable medium forwireless communication, comprising code that, when executed by at leastone processor, causes the at least one processor to: obtain a channelquality indicator (CQI) from a user equipment (UE); retrieve parametersfrom a modulation and coding scheme (MCS) table using the CQI, whereinthe table has entries corresponding to different spectral efficiency(SE) values selected to allow the BS to efficiently allocate resourcesat low SE values to achieve at least a target block error rate (BLER);and send a transmission to the UE based on the retrieved parameters. 20.A computer readable medium for wireless communication, comprising codethat, when executed by at least one processor, causes the at least oneprocessor to: determine a channel quality indicator (CQI) based onmeasurement of signals from a base station; determine a rank indicator(RI) value; and signal the CQI to the base station, wherein the CQIvalue is used to indicate the RI value.